If A is a matrix of order 3 and |adj A| = 7 , then the value of |A| is
Answer & explanation
Correct answer: option 3
We know that |adj A| = \( { |A| }^{ n-1 } \) , where n is the order of matrix A.
So, |adj A| = \( { |A| }^{ 3-1 } \) = \( { |A| }^{ 2 } \)
7 = \( { |A| }^{ 2 } \)
|A| = \(\sqrt { 7 }\), -\(\sqrt { 7 }\)